Heat saving device



FIG. 1 is a perspective view showing the left side, front and a portion of the top of the heat saving device showing my new design;

FIG. 2 is a front elevational view of the heat saving device;

FIG. 3 is a rear elevational view;

FIG. 4 is a right side elevational view;

FIG. 5 is a top plan view; and

FIG. 6 is a bottom plan view. 

The ornamental design for a heat saving device, as shown. 